Method and fingerprint sensing system for forming a fingerprint representation

1. A method of forming a fingerprint representation of a fingerprint pattern of a finger captured using a fingerprint sensor, the method comprising the steps of:

acquiring a first partial image of a corresponding first portion of a fingerprint pattern using the fingerprint sensor;

extracting a first fingerprint feature from the first partial image;

acquiring a second partial image of a corresponding second portion of the fingerprint pattern using the fingerprint sensor, the second partial image being non-overlapping with the first partial image;

extracting a second fingerprint feature from the second partial image;

determining a first parameter for each of the first and the second fingerprint feature, the first parameter being at least one of a representation of a relative spatial fingerprint position for the respective fingerprint feature and a representation of a relation of the fingerprint feature to the finger; and

forming the fingerprint representation by correlating the first parameter for the first fingerprint feature with the first parameter for the second fingerprint feature, wherein the fingerprint representation comprises an incomplete fingerprint image.

2. The method according to claim 1 , wherein the second partial image is acquired at a subsequent instance in time in comparison to the acquisition of the first partial image, and the step of determining the first parameter for each of the first and the second fingerprint feature comprises at least one of:

determining a duration between the acquisition of the first and the second partial image, and

determining a speed of the finger being swiped over the fingerprint sensor.

3. The method according to claim 2 , further comprises the step of determining a spatial relation between the first and the second fingerprint feature based on the first parameter.

4. The method according to claim 1 , wherein the first parameter for the first fingerprint feature and the first parameter for the second fingerprint feature are related to the same finger of a user.

5. The method according to claim 1 , wherein the extraction of the first fingerprint feature from the first partial image is performed independent of the extraction of the second fingerprint feature from the second partial image.

6. The method according to claim 1 , wherein the fingerprint sensor is a line sensor.

7. The method according to claim 2 , further comprising the step of determining the position of the finger at an instance in time of acquiring the first and the second partial image.

8. The method according to claim 7 , wherein the fingerprint sensor is arranged adjacently to a touch display, and the step of determining the position of the finger is based on data received from the touch display.

9. The method according to claim 1 , further comprising the steps of

acquiring a fingerprint template representative of an enrolled fingerprint of a finger, and

authenticating the formed fingerprint representation.

10. A fingerprint sensing system, comprising:

a fingerprint sensor;

a memory; and

processing circuitry for forming a fingerprint representation of a fingerprint pattern of a finger captured using the fingerprint sensor, the processing circuitry connected to the fingerprint sensor and further configured for:

acquiring a first partial image of a corresponding first portion of a fingerprint pattern using the fingerprint sensor;

extracting a first fingerprint feature from the first partial image;

acquiring a second partial image of a corresponding second portion of the fingerprint pattern using the fingerprint sensor, the second partial image being non-overlapping with the first partial image;

extracting a second fingerprint feature from the second partial image;

determining a first parameter for each of the first and the second fingerprint feature, the first parameter being at least one of a representation of a relative spatial fingerprint position for the respective fingerprint feature and a representation of a relation of the fingerprint feature to the finger; and

forming the fingerprint representation by correlating the first parameter for the first fingerprint feature with the first parameter for the second fingerprint feature, wherein the fingerprint representation comprises an incomplete fingerprint image.

11. The fingerprint sensing system according to claim 10 , wherein said fingerprint sensor is a capacitive fingerprint sensor.

12. The fingerprint sensing system according to claim 10 , wherein the fingerprint sensor is a line sensor.

13. The fingerprint sensing system according to claim 10 , wherein the processing circuitry is further configured for:

acquiring a fingerprint template representative of an enrolled fingerprint of a finger, and

authenticating the formed fingerprint representation.

14. The fingerprint sensing system according to claim 10 , wherein the second partial image is acquired at a subsequent instance in time in comparison to the acquisition of the first partial image, and the step of determining the first parameter for each of the first and the second fingerprint feature comprises at least one of:

determining a duration between the acquisition of the first and the second partial image, and

determining a speed of the finger being swiped over the fingerprint sensor.

15. The fingerprint sensing system according to claim 14 , wherein the processing circuitry is further configured determine a spatial relation between the first and the second fingerprint feature based on the first parameter.

16. An electronic device, comprising:

the fingerprint sensing system according to claim 10 ; and

at least one processor for:

providing an authentication request for said finger to the fingerprint sensing system;

receiving an authentication signal from the fingerprint sensing system; and

performing at least one action only if said authentication signal indicates authentication success.

17. The electronic device according to claim 16 , wherein the electronic device is a mobile phone.

18. A computer program product comprising a non-transitory computer readable medium having stored thereon computer program means for controlling a portable electronic device, the portable electronic device comprising a fingerprint sensing system including a fingerprint sensor and processing circuitry, the fingerprint sensing system adapted for forming a fingerprint representation of a fingerprint pattern of a finger captured when swiped over the fingerprint sensor, wherein the computer program product comprises:

code for acquiring a first partial image of a corresponding first portion of a fingerprint pattern using the fingerprint sensor;

code for extracting a first fingerprint feature from the first partial image;

code for acquiring a second partial image of a corresponding second portion of the fingerprint pattern using the fingerprint sensor, the second partial image being non-overlapping with the first partial image;

code for extracting a second fingerprint feature from the second partial image;

code for determining a first parameter for each of the first and the second fingerprint feature, the first parameter being a representation of a relative spatial fingerprint position for the respective fingerprint feature and a representation of a relation of the fingerprint feature to the finger; and

code for forming the fingerprint representation by correlating the first parameter for the first fingerprint feature with the first parameter for the second fingerprint feature, wherein the fingerprint representation comprises an incomplete fingerprint image.

19. The computer program product according to claim 18 , wherein the second partial image is acquired at a subsequent instance in time in comparison to the acquisition of the first partial image, and the code for determining the first parameter for each of the first and the second fingerprint feature comprises at least one of:

code for determining a duration between the acquisition of the first and the second partial image, and

code for determining a speed of the finger being swiped over the fingerprint sensor.

20. The computer program product according to claim 19 , further comprising code for determining a spatial relation between the first and the second fingerprint feature based on the first parameter.